I have synthesized graphene oxide by following modified hummers method. in PXRD, for a gaphene oxide, generally peak appered around 2(theta)= 11 degree. Eventhough graphite peak also appeared at 26 degree (002) , some of them inicate graphene oxide(GO) peak as (002) or (001). attachment of functional groups definitly will increase the graphene interlayer spacing and shifting peak to lower end in the diffractogram. but how can we assign a plane to graphene oxide?. so, what is the best way to explain the origin of graphene oxide peak as well as suitable plane ? (001) or something else ?